1. What is BMI?

Body Mass Index (BMI) is a person's weight in kilograms divided by the square of height in meters. For children and teens, BMI is age- and sex-specific and is often referred to as BMI-for-age according to CDC guidelines.

2. How Does the Calculator Work?

The calculator uses the standard BMI formula:

Where:

• \( weight \) — Body weight in kilograms (kg)
• \( height \) — Height in meters (m)

For children and teens (ages 2-19): The calculator provides BMI-for-age percentiles based on CDC growth charts.

3. Importance of BMI Calculation

Details: BMI is a screening tool that may indicate whether a person is underweight, at a healthy weight, overweight, or obese. For children, BMI-for-age shows how a child's BMI compares with others of the same age and sex.

4. Using the Calculator

Tips: Enter weight in kilograms, height in meters, and optionally age and gender for more specific interpretation. All values must be valid (weight > 0, height > 0).

5. Frequently Asked Questions (FAQ)

Q1: What is a healthy BMI range?
A: For adults, 18.5-24.9 is considered healthy. For children, consult CDC growth charts for age- and sex-specific percentiles.

Q2: How accurate is BMI?
A: BMI is a useful screening tool but doesn't directly measure body fat. Athletes may have high BMI due to muscle mass.

Q3: When should BMI-for-age be used?
A: For children and teens ages 2-19, BMI-for-age is more appropriate than standard BMI categories.

Q4: Are there limitations to BMI?
A: BMI doesn't account for muscle mass, bone density, overall body composition, or racial/ethnic differences.

Q5: How often should BMI be measured in children?
A: CDC recommends BMI screening annually for children ages 2 and older.